Electronic control systems for article sorting machines of the type which sort articles at ones of a plurality of discharge stations on the basis of the articles' weights are known. See U.S. Pat. No. 4,106,628 issued Aug. 15, 1978, incorporated herein by reference.
As is known in the art, in such sorting machines plural weight reference or weight cutoff values of successively increasing magnitude are selected and set into the controller by the operator. The range or differences between successive weight cutoff values define weight breaks or size grades into which the articles are to be classified. For example, the operator may desire to sort the articles into four weight breaks or size grades and accordingly will select four sequential weight cutoff values of successively increasing magnitude, defining the four weight breaks or size grades. These weight cutoff values are used by the controller to sort the articles into the various weight breaks on the basis of their actual weight.
It is often desirable to adjust the weight cutoff values during a sorting operation to maintain consistent package count and package weight throughout the sorting procedure. In prior art machines, this is achieved by manually readjusting the weight cutoff values during the sorting operation to account for variations in fruit weight. This requires that, during the sorting operation, the operator periodically sample package weight, calculate new weight cutoff values based upon the sample measurements, and input the new weight cutoff values into the control system. This manual sampling method often requires several minutes, and the weight distribution of the articles (which generally follows a Gaussian curve) may change dramatically in those few minutes. Drastic errors in package count and package weight may occur.
It is therefore desirable to provide a system which automatically adjusts the weight cutoff values during the sorting operation to achieve consistent package weight and package count throughout the sorting procedure.